Separating, transitional flow affected by various inflow oscillation regimes

A series of direct numerical simulations of laminar separation bubble flow with oscillating oncoming flow has been performed. A study is made of the influence of the amplitude and the period of the inflow oscillation on the dynamics of the separation bubble. The oscillating inflow is found to cause the location of separation and the location of transition to alternately move upstream and downstream. For all simulations, in every period a new separation bubble is formed as the inflow decelerates. The growth-rate of the triggered Kelvin–Helmholtz (KH) instability is found to depend on both the amplitude and the period of the inflow oscillation.